Does anyone know if there were 2 four spd opt. in 1975? Like a wide ratio & close ratio trans, and what were they? My 1975 has a T-10 and feels like a close ratio, but it has been so long since I drove a 4 spd GM tha I can't be sure since my tach is not working. Thanks for any help with this. RD. Packrat

Looking at the C3 Statistics on the Tools tab for the '75 model year I only see one 4-speed tranny listed (the M21), but on the '70 model year there are two 4-speeds listed(M21 & M22). From what I know about them the M22 was the heavy duty (aka "Rock-Crusher") version, but both show as being close-ratio. I don't have the years memorized that the M22 was available, but I'm sure someone out there does!

OK, here's what I found. There were 2 tranny's available, M20 Wide ratio and M21 short ratio, in 1975. The M20 was ONLY available with the L-82 enigine option. It looks like most 4 speeds were the M21 (1057 to be exact). Hope this helps